Diabetics, both type I and type II, who take insulin must measure the levels of their blood glucose at various times to know how much food or insulin to take to compensate for their present state. For many years, blood glucose has been measured by taking a lancing device from a pocket, purse, or testing kit, lancing through the skin of a patient's finger into the capillary bed, extracting a small drop of blood onto a test strip, and measuring the blood glucose concentration using an electronic blood glucose meter or color chart.
Specifically, to make this blood glucose measurement, a fresh test strip is first removed from a carrying case, and inserted into the blood glucose meter. A lancing device, which has a spring-loaded point tip or lancet, is then employed to prick through the skin into the patient's capillary bed, usually on a fingertip. Sometimes, particularly when the ambient temperature is cool, the finger must be “milked” or manually squeezed toward or around the lanced site to get a drop of blood that is large enough to analyze. This drop of blood is wicked into or placed on the test strip, where a chemical reaction takes place, which enables the meter to yield a measurement of the blood glucose concentration in that blood sample.
The step of getting the blood onto or into the test strip usually involves picking up the meter with a test strip already in place and moving the tip of the test strip to touch the exposed surface of the drop of blood on the pricked fingertip. The test strip usually includes a capillary or absorbent material that wicks the blood onto a glucose oxidase region, where the blood is then analyzed for blood glucose concentration.
The resultant blood glucose measurement is displayed on the meter's display screen, so that the patient can subsequently take insulin or eat food, as appropriate. Once the analysis of the blood sample is complete and the result displayed, the patient must use a tissue or similar material to remove any excess blood on the fingertip or other site from which the sample was taken. The used test strip is removed from the meter and carefully discarded. Care is taken to avoid touching the end of the strip, which still contains blood. Wiping the end of the strip with a tissue helps to remove the possibility of unwanted blood stains.
Conventionally, the taking of a blood sample for blood glucose measurement involves multiple steps, requires fresh testing supplies and equipment, specifically a lancing device and blood glucose meter. The production can take substantial time to complete for the diabetic. The supplies and equipment must be on-hand wherever the diabetic goes. Additionally, blood glucose testing is noticeable by individuals around the patient and is often an awkward or embarrassing procedure to complete in public settings due to the drawing of blood, meter usage, and clean up. Therefore, patients are often compelled to postpone the process to a more private setting so they are not embarrassed by the obtrusiveness of the process.
Attempts to improve the sampling and testing process self-performed by a patient have been made. For example, U.S. Patent Application Publication No. 2008/0077048, to Escutia et al., teaches a body fluid sampling device to automate milking of a patient digit to express a sufficient amount of body fluid. The device includes a catalyst device to apply pressure to the digit and a footprint. The digit is positioned within the catalyst, which directs blood to a sampling site on the digit, and over the footprint. The footprint guides the penetration member to the digit. However, the patient must remove his digit from the catalyst to clean up any excess blood.
U.S. Pat. No. 7,004,928 and U.S. Patent Application Publication No. 2006/0094985 to Aceti et al. teach a monitoring and drug delivery device that provides calibration and semi-continuous monitoring. The device includes a carrier having a plurality of microneedles, each coupled with a conduit, and a plurality of microchannels. One of the microneedles penetrates the skin of a patient and a blood sample is obtained, which enters the associated microchannel. After the microneedle punctures the skin, the patient must manually wipe any excess blood with a tissue.
Further, U.S. Pat. No. 6,540,675, U.S. Pat. No. 6,923,764, and U.S. Patent Application Publication No. 2004/0202576, also to Aceti et al., teach an analyte monitor having a plurality of needles each associated with a chamber configured to hold a blood sample. The sample is collected into the chamber by piercing the skin of a patient with the needle. Once collected, an arm including a detector and light source rotates to the chambers to emit a light source. An absorbance of the light is detected. Once punctured, the patient must manually clean any excess blood from the site of the pierced skin.
Therefore, a need remains for a blood glucose sampling device, which could be used by patients without having to assemble all the various supplies and equipment to accomplish the task of making a blood glucose measurement. A blood glucose sampling device that is more discrete would allow patients to make blood glucose measurements without the embarrassment of nearby people being aware that the process is taking place.